Experimental Animal Model for the Study of Immunity to Entamoeba Histolytica.

摘要

Comparing experimental hepatic amebiasis in LHC/Lak inbred hamsters with amebic liver abscess as described in man demonstrated the validity of this animal model. An extensive bibliography and review of the literature were given in addition to experimental results. Adult male hamsters were surgically infected via the portal vein with axenically cultivated trophozoites of Entamoeba histolytica. At doses of 50 to 315 thousand amebae, strain HM-1:IMSS was the most pathogenic; 200:NIH was intermediate; HU-21:AMC and HK-9 were nonpathogenic. The model exhibited a spectrum of disease depending upon the dose and strain of amebae. Strain 200:NIH provided an opportunity to study healing lesions beginning seven days after infection. Strain HM-1:IMSS was the overall best choice for the model because it caused an infection that mimicked the human disease. Within 48 days after infection, HM-1:IMSS proved lethal to 80% of the animals in a separate group that received the highest dose. Within 15 days this virulent strain caused multifocal caseous necrosis of the liver and hepatomegaly. Gross lesions were solid, and the chronic inflammation involving them was granulomatous with the macrophage being the principal inflammatory cell. Severely infected animals suffered loss of body weight and had a blood picture similar to that of patients with amebic liver abscess. Mild anemia accompanied neutrophilic leukocytosis diminishing with chronicity of the infection.